This super small mono amplifier is surprisingly powerful, able to deliver up to 2.5 Watts into 4-8 ohm impedance speakers. Inside the miniature chip is a class D controller, able to run from 2.0V-5.5VDC. Since the amp is a class D, its very efficient (over 90% efficient when driving an 8 speaker at over half a Watt), making it perfect for portable and battery-powered projects. It has built in thermal and over-current protection but we could barely tell it got hot. There's even a volume trim pot so you can adjust the volume on the board down from the default 24dB gain. This board is a welcome upgrade to basic "LM386" amps! CJMCU The A+ and A- inputs of the amplifier go through 1.0uF capacitors, so they are fully 'differential' - if you don't have differential outputs, simply tie the Audio- pin to ground. The output is "Bridge Tied", that means the output pins connect directly to the speaker pins, no connection to ground. The output is a high frequency 250KHz square wave PWM that is then 'averaged out' by the speaker coil, the high frequencies are not heard. All the above means that you can't connect the output into another amplifier, it should drive the speakers directly. CJMCU Comes with a fully assembled and tested breakout board. We also include header to plug it into a breadboard and a 3.5mm screw-terminal blocks so you can easily attach/detach your speaker. You will be ready to rock in 15 minutes! Speaker is not included, use any 4 ohm or greater impedance speaker. Output Power: 2.5W at 4, 10% THD, 1.5W at 8, 10% THD, with 5.5V Supply 50dB PSRR at 1KHz Filterless design, with ferrite bead + capacitors on output. Fixed 24dB gain, onboard trim potentiometer for adjusting input volume. Thermal and short-circuit/over-current protection; Low current draw: 4mA quiescent and 1uA in shutdown mode